Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D45/00—Clamping or other pressure-applying devices for securing or retaining closure members
  • B65D45/02—Clamping or other pressure-applying devices for securing or retaining closure members for applying axial pressure to engage closure with sealing surface
  • B65D45/16—Clips, hooks, or clamps which are removable, or which remain connected either with the closure or with the container when the container is open, e.g. C-shaped
  • B65D45/20—Clips, hooks, or clamps which are removable, or which remain connected either with the closure or with the container when the container is open, e.g. C-shaped pivoted
  • B65D45/24—Clips, hooks, or clamps which are removable, or which remain connected either with the closure or with the container when the container is open, e.g. C-shaped pivoted incorporating pressure-applying means, e.g. screws or toggles
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
  • H02G3/00—Installations of electric cables or lines or protective tubing therefor in or on buildings, equivalent structures or vehicles
  • H02G3/02—Details
  • H02G3/08—Distribution boxes; Connection or junction boxes
  • H02G3/088—Dustproof, splashproof, drip-proof, waterproof, or flameproof casings or inlets

Definitions

• the present disclosure relates generally to explosion-proof enclosures, and more particularly to systems, methods, and devices for securing a cover of an explosion-proof enclos ure to a body of the explosion-proof enclosure.
• Explosion-proof receptacle housings and enclosure systems are used in many different industrial applications. Such explosion-proof receptacle housing and enclosure systems may be used, for example, in military applications, onboard ships, assembly plants, power plants, oil refineries, petrochemical plants, and other harsh environments. At times, the equipment located inside such explosion-proof receptacle housing and enclosure systems is used to control motors and other industrial equipment.
• the disclosure relates to an enclosure.
• the enclosure can include a first enclosure portion having a first flange, at least one first engagement feature disposed on a. first inner surface of the first enclosure portion, and at least one mounting support.
• the enclosure can also include a second enclosure portion mechanically coupled to the first enclosure portion and having a second flange and at feast one second engagement feature disposed on a second inner surface of the second enclosure portion.
• the enclosure can further include at least one fastening device mechanically and movably coupled to the at least one mounting support, where the at least one fastening device engages the first flange and the second flange when the at least one fastening device is in a closed position, where the at least one fastening device is disengaged from the first flange and the second flange when the at least one fastening device is in an open position.
• the at least one first engagement feature can couple to the at least one second engagement feature when the at least one fastening device is in the closed position.
• a first flame path can be maintained between the first flange and the second flange when the at least one fastening device is in the closed position.
• Figures 2A and 2B show cross-sectional side perspective views of the explosion-proof enclosure of Figure 1 detailing the example fastening devices in accordance with certain example embodiments.
• Figures 3A-3C show various views detailing the example fastening device of Figures 1 -2B in accordance with certain example embodiments.
• FIG. 4 shows a front perspective view of an explosion-proof enclosure with another example fastening device in accordance with certain example embodiments.
• Figures 5 A and 5B sho cross-sectional side perspective views of the explosion-proof enclosure of Figure 4 detailing the example fastening device in accordance with certain example embodiments.
• the example embodiments discussed herein are directed to systems, apparatuses, and methods of fastening a cover of an explosion-proof enclosure to a body of the explosion-proof enclosure. While the example embodiments discussed herein are with reference to explosion-proof enclosures, other types of non-explosion- proof enclosures (e.g. , junction boxes, control panels, fighting panels, motor control centers, switchgear cabinets, relay cabinets) or any other type of enclosure (e.g., hazardous enclosure) may be used in conjunction with example embodiments of fastening devices.
• non-explosion- proof enclosures e.g. , junction boxes, control panels, fighting panels, motor control centers, switchgear cabinets, relay cabinets
• any other type of enclosure e.g., hazardous enclosure
• cover and the body of an enclosure can be referred to as enclosure portions.
• example fastening devices are shown in the accompanying figures as being mechanically coupled to the cover of an enclosure, example fastening devices can, additionally or alternatively, be mechanically coupled to the body of the enclosure.
• example flange relief features are shown being disposed on the body, example flange relief features can, additionally or alternatively, be disposed on the cover.
• an explosion-proof enclosure [0016] In one or more example embodiments, an explosion-proof enclosure
• a joint may be a mating of any two or more surfaces. Each surface may be any type of surface, including but not limited to a flat surface, a threaded surface, a rabbet surface, and a serrated surface,
• an explosion-proof enclosure is subject to meeting certain standards and/or requirements.
• NEMA sets standards with which an enclosure must comply in order to qualify as an explosion- proof enclosure.
• NEMA Type 7, Type 8, Type 9, and Type 10 enclosures set standards with which an explosion-proof enclosure within a hazardous location must comply.
• a NEMA Type 7 standard applies to enclosures constructed for indoor use in certain hazardous locations.
• Hazardous locations may be defined by one or more of a number of authorities, including but not limited to the National Electric Code (e.g., Class I, Division 1) and Underwriters' Laboratories, Inc. (UL) (e.g., UL 1203).
• UL Underwriters' Laboratories, Inc.
• a Class I hazardous area under the National Electric Code is an area in which flammable gases or vapors may be present in the air in sufficient quantities to be explosive.
• NEMA standards for an explosion-proof enclosure of a certain size may require that in a Group B, Division 1 area, any flame path of an explosion-proof enclosure must be at least I inch long (continuous and without interruption), and the gap between the surfaces cannot exceed 0.0015 inches.
• Standards created and maintained by NEMA may be found at www.nema.org/stds and are hereby incorporated by reference.
• Example embodiments described herein require the use of a tool, whether custom made or standard, to disengage the fastening device and open the explosion-proof enclosure.
• Each of the components of the example fastening devices e.g., fastener, fastener receiver, load distributing member, handle, cam, pin
• Example enclosures described herein can be exposed to one or more environments (e.g. , hazardous, corrosive, high temperature, high humidity) that can cause the enclosure cover and the enclosure body to become fused together to some extent.
• example cover release mechanisms can be used to assist in prying apart the enclosure cover from the enclosure body.
• a cover release mechanism can be useful when oxidation has formed between the cover flange and the body flange.
• an improper method of prying apart the enclosure cover and the enclosure body can result in damage (e.g. , scoring, pitting, gouging) to the cover flange and/or the body flange.
• Examples of cover release mechanisms can be found in United States Patent Application Serial Number 13/794,433 entitled “Cover Release Mechanisms for Enclosures," the entire contents of which are hereby incorporated by reference.
• Example embodiments of fastening devices for explosion-proof enclosures will be described more fully hereinafter with reference to the accompanying drawings, in which example embodiments of fastening devices for explosion-proof enclosures are shown.
• Fastening devices for explosion-proof enclosures may, however, be embodied in many different forms and should not be construed as limited to the example embodiments set forth herein. Rather, these example embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of fastening devices for explosion-proof enclosures to those or ordinary skill in the art.
• Like, but not necessarily the same, elements (also sometimes called components) in the various figures are denoted by like reference numerals for consistency.
• Figure 1 shows a front perspective view of an explosion-proof enclosure 100 with example fastening devices 1 10 in accordance with certain example embodiments.
• one or more of the features shown in Figure 1 may be omitted, added, repeated, and/or substituted. Accordingly, embodiments of an explosion-proof enclosure with fastening devices should not be considered limited to the specific arrangements of components shown in Figure I .
• the explosion-proof enclosure 100 includes an enclosure cover 102 and an enclosure body 104.
• the enclosure cover 102 can include an elevated inner portion 120, an outer portion 121 , one or more transitional supports 124 between the elevated inner portion 120 and the outer portion 121 , and a cover flange 122 disposed around the perimeter of the outer portion 121 of the enclosure cover 102.
• a wall 123 can join the elevated inner portion 120 and the outer portion 121.
• the wall 123 cars also be coupled to one or more of the transitional supports 124.
• the enclosure body 104 includes a base 130 having a back and one or more wails adjacent to the back.
• the enclosure body 104 can also include a body flange 132 disposed at the end of the one or more walls of the base 130.
• the body flange 132 can be disposed around the perimeter of the base 130 of the enclosure body 104,
• the cover flange 122 is mated to a body flange 132.
• the interior surface 222 of the cover flange 122 is mated to the interior surface 232 of the body flange 132.
• the fastening device 1 10 is disposed along the top end of the enclosure 100.
• more than one fastening device 1 10 disposed toward one or more ends and/or sides of the enclosure 100 can be used.
• the fastening device 110 can have an open position (where the fastening device 1 10 is not engaging the cover flange 122 and the body flange 132) and a closed position (where the fastening device 1 10 is engaging the cover flange 122 and the body flange 132).
• the fastening device 1 10 is shown in the closed position.
• the air gap that forms between the surfaces of the cover flange 122 and the body flange 132 when the cover flange 122 and the body flange 132 converge is the flame path 169.
• the flame path 169 is formed between the interior surface 222 of the cover flange 122 and the interior surface 232 of the body flange 132, beginning from the interior of the enclosure until the path between the interior surface 222 and the interior surface 232 is interrupted, as by a sealing member
• One of the functions of the fastening device HO is to ensure that the flame path 169 is within an accepted tolerance in light of a particular standard for the explosion-proof enclosure 100.
• the enclosure cover 102 (sometimes generically called an enclosure portion) and the enclosure base 104 (sometimes also generically called an enclosure portion) of the explosion-proof enclosure 100 are secured using the fastening device 1 10.
• the fastening device 110 in this case includes a bracket 148.
• the bracket 148 as shown in Figure I is substantially U-shaped, but the bracket 148 can also have one or more of a number of other shapes.
• the bottom side 152 of the bracket 148 can be antiparallel to the top side 150, where the top side 150 is substantially perpendicular to the back side 154 that joins (mechanically couples) the top side 150 and the bottom side 152.
• the back side 154 can form a single piece with the top side 150 and/or the bottom side 152, as in a forged manufacturing process.
• the back side 154 can be a separate member that is mechanically coupled to the top side 150 and'or the bottom side 152.
• the back side 154 can be mechanically coupled to the top side 150 and/or the bottom side 152 using one or more of a number of methods, including but not limited to welding, fastening devices, epoxy, and overlaying brackets, and slotted receivers.
• the bracket 148 includes one or more of a number of optional features.
• one or more optional ribs can be disposed substantially vertically along the inner surface of the back side 154 of the bracket 148.
• the ends of each rib may be disposed on the bottom surface of the top side 150 and'or on the top surface of the bottom side 152. of the bracket 148.
• Any such ribs can be of any dimensions (e.g., length, width, height, thickness) and/or shape.
• the dimensions of a 124 can be substantially similar to some or all other ribs disposed on the underside of the bracket 148.
• the ribs can be used for one or more other purposes.
• the ribs can be used to properly position and maintain contact by the bracket 148 with a particular portion of the cover flange 122 and/or the body flange 132.
• recesses can be cut into one or more surfaces of the cover flange 122 and'or the body flange 132 that contact the ribs when the bracket 148 is properly positioned.
• Each example recess can have dimensions (e.g., depth, width, length) that are slightly larger than the corresponding dimensions of the rib that mechanically couples with the recess.
• a recess can be cut into an outer edge of the cover flange 122, an outer edge of the body flange 132, a top surface of the cover flange 122, and/or a bottom surface of the body flange 132.
• the top side 150 of the bracket 148 is longer than the bottom side 152.
• the length of the top side 150 can depend on one or more of a number of factors, including but not limited to the size of the cover 102, the thickness of the top side 150, and the location of any components (e.g. , indicating lights, switch handle, viewing window) disposed on the surface of the cover 102.
• bracket 148 can be made thicker to improve the structural integrity of the bracket 148.
• the added thickness of the bracket 148 can extend to all or select portions (i.e., the top side 150, the bottom side 152, and the back side 154) of the bracket 148,
• the added thickness of the bracket 148 can be made to all or select portions of the top side 150, the bottom side 152, and/or the back side 154.
• the thickness of the bracket can be measured with or without consideration of the ribs 124 on the under side of the bracket 148.
• the bracket 148 contacts at least a portion of the top surface (the outer portion 121) of the cover flange 122 (and also, in some cases, wall 123 and/or the elevated inner portion 120), and the bottom side 152 of the bracket 148 contacts at least a portion of the bottom surface of the base flange 132.
• the cover flange 122 and/or the body flange 132 is shaped to conform to the bracket 148.
• the bottom portion of the body flange 132 includes a chamfer that is formed at a downward angle that is substantially parallel to the bottom side 152 of the bracket 148 when the bracket 148 is engaged with the explosion-proof enclosure 100.
• the bottom side 152 is substantially perpendicular to the back side 154, and the top side 150 is antiparallel to the bottom side 152.
• the body flange 132 does not include the chamfer, but the top portion of the cover flange 122 does include a chamfer that is cut at an upward angle and is substantially parallel to the top side 150 of the bracket 148 when the bracket 148 is engaged with the explosion-proof enclosure 100.
• the top side 150 of the bracket 148 can include an engagement portion
• the engagement portion is located at the distal end of the top side 150 and is mechanically coupled to the lever 140 (described below).
• the engagement portion can form a single piece with the top side 150, as in a forged manufacturing process.
• the engagement portion can be a separate member that is mechanically coupled to the top side 150.
• the engagement portion can be mechanically coupled to the top side 150 using one or more of a number of methods, including but not limited to welding, fastening devices, epoxy, and overlaying brackets, and slotted receivers.
• the engagement portion can be fixedly coupled or movably (e.g., hingedly) coupled to the lever 140.
• the fastening device 1 10 is
• the top side 150, the back side 154, and'or the bottom side 152 each can have an array of protrusions.
• Such protrusions can serve one or more of a number of purposes.
• the protrusions can provide structural reinforcement and maintain mechanical integrity of the bracket 148.
• Each protrusion can be of any height and/or thickness.
• each protrusion can have varying heights and/or thicknesses along the length of the protrusion.
• the protrusions can form a single piece with the bracket 148, as in a forged manufacturing process.
• the protrusions can be separate members that are mechanically coupled to the bracket 148.
• the protrusions can be mechanically coupled to the bracket 148 using one or more of a number of methods, including but not limited to welding, fastening devices, epoxy, and overlaying brackets, and slotted receivers.
• the fastening device 110 can include a lever 140.
• the lever 140 can include a handle 144 located at the distal end, a body 142, and a hinged coupling feature 146 (which can also be called a retaining feature or a detent) at the proximal end.
• the lever 140 is mechanically coupled to the top side 150 using the hinged coupling feature 146.
• the hinged coupling feature 146 can hingedly couple to a corresponding engagement portion of the top side 150.
• a tubular aperture can traverse the length of both the hinged coupling feature 146 and the engagement portion, and the two pieces are joined by inserting a pin (described below with respect to Figures 3A-3C) into the apertures.
• the pin maintains the hinged coupling between the bracket 148 and the lever 140.
• the lever 140 can also be mechanically coupled to the bracket 148 in one or more of a number of other ways. In any case, when the lever 140 is engaged, the coupling between the lever 140 and the bracket 148 causes the bracket 148 to become engaged with the enclosure 100. Likewise, when the lever 140 is disengaged, the coupling between the lever 140 and the bracket 148 causes the bracket 148 to become disengaged from the enclosure 100.
• the coupling feature 146 can be used to mechanically couple other various components of the fastening device 1 10 and/or explosion-proof enclosure 100 to each other.
• the coupling feature 146 can mechanically couple the enclosure cover 102 to the bracket 148.
• the coupling feature 146 can mechanically couple the enclosure body 104 to the bracket 148.
• the coupling feature 146 can include one or more pieces that can each have one or more of a number of features (e.g., sliding features, hinged features, fastening receivers) to allow the coupling feature 146 to couple together components of the fastening device 110 and/or explosion-proof enclosure 100.
• the fastening device 110 (or portions thereof) are mechanically and rnovab!y coupled to at least one mounting support 180, where the mounting support 180 is mounted to the outer surface of the enclosure cover 102.
• at least one mounting support 180 can be mechanically coupled to the wall 123 that joins the elevated inner portion 120 and the outer portion 121 of the enclosure cover 102.
• the at least one mounting support 180 can be disposed on the outer portion 121 adjacent to the elevated inner portion 120.
• the mounting support. 1 80 can be mounted on the enclosure cover 102 using one or more methods, including but not limited to welding, fastening devices, and mating threads.
• two mounting supports 180 and the wall 123 form a single piece, as from a casting process.
• the mounting supports 180 can be mechanically coupled to the enclosure body 104.
• Each mounting support can include a. fastener 1 14.
• the fastener 114 can adjust the compressive force applied by the fastening device 1 10 and is discussed in more detail below with respect to Figures 3A-3C.
• the hinged coupling feature 146 of the fastening device 1 10 is hingedly coupled to the mounting supports 180 and fixedly coupled to the bracket 148. Further, the handle 144 is fixedly coupled to the hinged coupling feature 146 and allows the fastening device 1 10 to move between the open position and the closed position.
• Figures 2A and 2B show cross-sectional side perspective views of an enclosure system 200 that includes the explosion-proof enclosure of Figure 1 and detailing the example fastening device 110 in accordance with certain example embodiments.
• Figure 2A shows the enclosure cover 102 mechanically coupled to the enclosure body 104.
• Figure 2.B shows the enclosure cover 102 mechanically decoupled from the enclosure body 104.
• one or more of the features shown in Figures 2A and 2B may be omitted, added, repeated, and/or substituted. Accordingly, embodiments of an explosion-proof enclosure with fastening devices should not be considered limited to the specific arrangements of components shown in Figures 2A and 2B.
• the fastening device is partly disposed on the enclosure cover 102 and partly on the enclosure body 104.
• at least one engagement feature 225 of the fastening device is disposed on the inner surface of the enclosure cover 102.
• each engagement feature 225 is disposed on the back side of the outer portion 121 of the enclosure cover 102.
• at least one engagement feature 235 which complements the engagement feature 225, is disposed on the enclosure body 104.
• each engagement feature 235 can be disposed on an inner surface of a side wall of the enclosure body 104.
• the engagement feature 225 can have one or more of a. number of shapes and features.
• the engagement feature 225 can have a base 226 that is coupled to the enclosure cover 102 and a mating feature 227.
• the mating feature 227 is shown having a wedge shape, but the mating feature 227 can have one or more of a number of other shapes, including but not limited to an arc, a square, a sawtooth, and a sinusoid.
• the width (thickness) of each engagement feature 225 can vary, and can be substantially uniform or variable along its length.
• the engagement feature 235 can have one or more of a. number of shapes and features that complement those of the engagement feature 225 to which the engagement feature 235 couples. As shown in Figures 2 A and 2B, the engagement feature 235 can have a base 236 that is coupled to the enclosure cover 102 and a mating feature 237. For example, if the shape of the mating feature 227 for the engagement feature 225 is a wedge or triangle, then the shape of the mating feature 237 for the engagement feature 235 can also be a wedge or triangle that complements the mating feature 227 so that the engagement feature 225 can mechanically couple to the engagement feature 235 when the fastening device 110 is in the closed position.
• the engagement feature 225 disposed on the inner surface of the enclosure cover 102 is adjustable to ensure that the flame path 169 between the cover flange 122 and the body flange 132 complies with specifications.
• the engagement feature 235 disposed on the inner surface of the enclosure body 104 is adjustable (as by a user or a manufacturer) to ensure that the flame path 169 between the cover flange 122 and the body flange 132 complies with specifications.
• the engagement feature 2,35 can be adjusted by a manufacturer so that the flame path 169 complies with specifications upon first use by a. user.
• the engagement feature 235 can be adjusted by a user to compensate for wear and/or maintenance over time so that the flame path 169 complies with specifications.
• the engagement feature 225 and/or the engagement feature 235 can be adjustable in one or more of a number of ways.
• the engagement feature 225 can be disposed within a track (e.g., a slot) that is continuous or has a number of discrete positions along its length. In such a case, the engagement feature 225 can be moved by a user to help ensure a proper flame path 169 between the cover flange 122 and the body flange 132.
• the engagement feature 235 can have a fastening feature (e.g., an aperture that traverses therethrough) that couples (either directly or using an additional device, such as a bolt) to one of a number of complementary fastening features (e.g., apertures that traverse into a portion of a wall).
• a fastening feature e.g., an aperture that traverses therethrough
• an additional device such as a bolt
• the engagement features 225 move in response to movement of the fastening device 1 10.
• the engagement features 225 also move.
• the engagement features 225 become engaged with (mechanically couple to) the engagement features 235,
• the engagement features 235 can move in response to movement of the fastening device 1 10.
• the enclosure cover 102 when the fastening device 1 10 is in the open position, the enclosure cover 102 can be decoupled (removed) from the enclosure body 104. If the engagement features 225 and/or the engagement features 235 do not move in response to the movement of the fastening device 110, then the enclosure cover 102 may have to be moved in a certain direction (e.g., upward) before the enclosure cover 102 can be removed from the enclosure body 104,
• the hinged coupling feature 146 and the mounting supports 180 can be joined by inserting a pin 21 1 into apertures that traverse some or all of the hinged coupling feature 146 and the mounting supports 180. The pin 21 1 can maintain the hinged coupling between the hinged coupling feature 146 and the mounting supports 180 and allow the fastening device 1 10 to move between the closed position and the open position.
• Figures 2A and 2B also sho how the rear surface 131 of the body flange 132. can be configured to engage the bottom side 152 of the bracket 148 of the fastening device 110.
• a portion 134 of the rear surface 131 of the body flange 132 can have a different contour than the rest of the rear surface 131.
• the shape and orientation of the portion 134 can be substantially the same as the shape and orientation of the inner surface of the bottom side 152 of the bracket 148 when the fastening device 110 is in the closed position.
• the portion 134 of the body flange 132 has a vertical profile that is less (and a horizontal profile that is more) than that of a remainder (i.e., the rest of the rear surface 131) of the body flange 132, where the bracket 148 engages the cover flange 122 and the portion 134 of the body flange 131 when the lever 140 is in the closed position, and where the bracket 148 is disengaged from the cover flange 122 and the portion 134 of the body flange 132 when the lever 140 is in the open position.
• a sealing member 294 (e.g., gasket, o-ring) is fit inside a channel (hidden from view by the sealing member 294) on the bottom surface of the cover flange 12.2. and/or the top surface of the base flange 132.
• the gasket 294 is compressed, providing a seal against ingress while providing a flame path 169 that meets one or more applicable standards (e.g. , flame path 169 no greater than 0.0015 inches).
• the sealing member 294 can be any type of sealing member (e.g., gasket, o-ring) made of a compressible material (e.g., rubber, silicon).
• the enclosure cover 102 and/or the enclosure body 104 can include a securing feature to help the enclosure cover 102 become properly aligned with the enclosure body 104 when the enclosure cover 102 is coupled to the enclosure body 104.
• the enclosure cover 102 can include a securing feature 283 disposed on the inner surface of the enclosure cover 102.
• the securing feature 283 can be disposed on any side (e.g., toward the bottom end) of the enclosure cover 102. In some cases, the securing feature 283 is positioned on a side opposite where the fastening device 110 is positioned.
• the securing feature 283 can have a shape and/or size thai complements the securing feature 285 disposed on the inner surface of the enclosure body 104.
• the shape and/or size of the securing feature 283 and the securing feature 285 can vary. [OOSO
• the securing feature 283 and/or the securing feature 285 can be segmented and/or have a single member with a size and shape that is substantially similar to the engagement feature 225 and/or the engagement feature 235, respectively.
• an additional feature 287 can be disposed on the inner surface of the enclosure cover 102 and/or the enclosure body 104 to help ensure that the interior surface 222 of the cover flange 122 has proper surface contact with the interior surface 232 of the body flange 132.
• Figures 3A-3C show various views detailing the example fastening device 110 shown in Figures 1 -2B for an explosion-proof enclosure 300.
• Figures 3A-3C each show a different cross-sectional side perspective view of the fastening device 110 to provide detail as to how, in certain example embodiments, the lever 140 is used to engage the bracket 148 with, and disengage the bracket 148 from, the enclosure 300.
• the bracket 148 engages the enclosure 300 when the lever 140 is put in the closed position, which occurs by pushing the handle 144 downward (or upward if the fastening device 110 is oriented in the opposite direction), toward the bracket 148.
• the cam 247 of the fastening device 110 is engaged and draws the bracket 148 toward the enclosure 300 (downward in Figures 3A-3C).
• the bottom side 152 of the bracket 148 supplies a compressive force to the base flange 132 against the cover flange 122 to reduce the flame path 169.
• An optional securing device 261 can be mechanically coupled to a portion (e.g., the top side 150) of the bracket 148.
• an optional securing device 261 traverses an aperture 160 in a portion (e.g. , along the body 142) of the lever 140 and engages that portion of the lever 140 to secure the lever 140 in the fully-closed (engaged) position.
• the securing device 261 is a screw that is disposed within and engages a slot in the aperture 160 in the body 142 of the lever 140 to secure the lever 140 against the bracket 148 when the lever 140 is in the fully-closed position.
• the securing device 261 provides tamper resistance and can require a tool (not shown) to release the lever 140.
• the tool can be a specially-designed tool or a standard tool (e.g., a screwdriver).
• Other examples of the securing device 261 can include, but are not limited to, a screw, a detent, and a bolt.
• the securing device 261 can be positioned in one or more of a number of different locations with respect to the lever 140.
• Other examples of a securing device are described in United States Patent Application Serial Number 13/794,402, entitled "Fastening Devices for Explosion-Proof Enclosures," fifed with the U.S. Patent and Trademark Office on March 1 1, 2013, and whose entire contents are hereby incorporated herein by reference.
• Figure 3B shows how the compressive force applied by the bracket
• a fastener 1 14 can be driven into and/or extracted from an aperture along the edge 299 of a mounting support 180, As shown in Figure 3B, the edge 299 of a mounting support 180 can be horizontal, vertical (as shown), or have a slope. When the fastener 114 is oriented horizontally through the edge 299, the fastener 114 can be driven into and/or extracted from the edge 299 of the mounting support 180. In such a case, as the fastener 114 is driven into and extracted away from the cam 247, a horizontal force is applied to and taken away from, respectively, the cam 247 by the optional wear plate 210. The optional wear plate 210 can be positioned between the edge 299 and the cam 247.
• the wear plate 210 can align with the aperture through the edge 299 that is traversed by the fastener 114.
• less force e.g. , 2/3 less force
• less effort may be used to drive the fastener 114 into and/or extract the fastener 1 14 from the edge 299 of a mounting support 180.
• less effort is required to adjust the compressive force applied by the bracket 148 through the cam 247.
• the wear plate 210 is used to apply the proper load to the cam 247, and which causes the proper amount of force to be applied by the bracket 148 on the enclosure 300 to provide a proper flame path 169. If too much clamping force is required of the cam 247, the flame path 169 will be too small, which could increase the pressure developed from an explosion inside the explosion-proof enclosure 300 and exceed the strength of the explosion-proof enclosure 300. If too little clamping force is required of the cam 247, the flame path 169 will be too large, which could let the flame escape from the explosion-proof enclosure 300, In either case, the standards required for an explosion-proof 300 may not be met.
• Figures 3A-3C help illustrate how moving the handle 144 to transition the lever 140 from the fully-closed position (as shown in Figures 3A and 3B) to the open position (as shown in Figure 3C) also moves the bracket 148 from engaging the enclosure 300 (specifically, the cover flange 122 and the body flange 132) to disengaging the enclosure 300, When this occurs, explosion-proof enclosure 300 can be opened.
• the engaging member 261 is released (in this case, unscrewed) from the aperture 160 within the body 142 of the lever 140. Releasing the engaging member 261 may be performed using a tool.
• the lever 140 is lifted upward by the handle 144 and toward the explosion-proof enclosure 300.
• the enclosure cover 102 is lifted in a certain direction (e.g., upward) so that the engagement features 225 become disengaged from the engagement features 235. Subsequently, the enclosure cover 102 can be moved away from the enclosure body 104.
• the cam 247 rotates and pushes the engagement portion (and thus the rest of the bracket 148) away from the enclosure 300.
• the distance that the engagement portion is pushed away from the enclosure 300 is limited by the extent that the wear plate 210 is positioned relative to the cam 247.
• the fastening devices 1 10 are mounted on the top surface of the enclosure cover 102, there is an area (e.g., the elevated inner portion 120) on the top surface of the enclosure cover 102 within which existing components (e.g., switches, indicating lights, pushbuttons) on the outer surface of the enclosure cover 102 can be located without interfering with the operation of such fastening devices 1 10.
• the size of this area can vary. For example, the dis tance between an edge of the enclosure cover 102 and the closest portion of the area may be two inches or less.
• the profile of a fastening device 1 10 can be relatively small.
• the distance between the top of the back side 154 of the bracket 148 and the top of the hinged coupling feature 146 and/or the handle 144 of the lever 140 should be as small as possible (e.g., no more than two inches).
• the distance between the bottom of the back side 154 and the end of the bottom side 152 can be minimal (e.g., no more than one inch).
• Such distances can be larger, particularly when example fastening devices 110 described herein are used to retrofit an existing explosion-proof enclosure that has bolts or other traditional fastening devices.
• the characteristics (e.g. , height, width, depth, location of components disposed on the cover) of the existing explosion-proof enclosure can dictate the size of the fastening device 1 10.
• Figure 4 shows a front perspective view of an explosion-proof enclosure 400 with another example fastening device 410 in accordance with certain example embodiments.
• one or more of the features shown in Figure 4 may be omitted, added, repeated, and/or substituted. Accordingly, embodiments of an explosion-proof enclosure with fastening devices should not be considered limited to the specific arrangements of components shown in Figure 4.
• the explosion-proof enclosure 400 (including the enclosure cover 402 and the enclosure body 404) of Figure 4 is substantially the same as the explosion-proof enclosure 100 of Figure 1 and the explosion-proof enclosure 200 of Figures 2A and 2B,
• the fastening devices 410 of Figure 4 are each operated by a cam 472 that traverses the enclosure cover 402. Specifically, the cam 472 can traverse the outer portion 421 (and'' or some other portion) of the enclosure cover 402. In such a case, an additional flame path 474 is created between the cam 472 and the enclosure cover 402.
• the cam 472 can be housed, at least in part, within a mounting support
• the mounting support 480 can be part of, or can be coupled to, the wall 423 (and/or some other portion) of the enclosure cover 402.
• the cam 472 can be rotated (opened and closed) using a tool (not shown), such as an hex- head wrench.
• the details of the fastening device 410 are shown in Figures 5A and 5B. While Figure 4 shows two fastening devices 410, example embodiments can have only one fastening device or more than two fastening devices. With multiple fastening devices 410, each fastening device can be positioned at any location along the top surface of the enclosure cover 402.
• Figures 5A and 5B each shows a cross-sectional side perspective view of an enclosure system 500 that includes the explosion-proof enclosure of Figure 4 and detailing the example fastening device 410 in accordance with certain example embodiments.
• Figure 4A shows the enclosure cover 402 mechanically coupled to the enclosure body 404.
• Figure 4B shows the enclosure cover 402 mechanically decoupled from the enclosure body 404.
• one or more of the features shown in Figures 4A and 4B may be omitted, added, repeated, and/or substituted. Accordingly, embodiments of an explosion-proof enclosure with fastening devices should not be considered limited to the specific arrangements of components shown in Figures 4A and 4B.
• a cam 472 includes a shaft 473 that traverses the thickness of the enclosure cover 402 (in this case, the cover flange 422) and is disposed within the mounting support 480. The end of the shaft 473, inside the enclosure body 404, is mechanically coupled to a fastening feature 474.
• a portion of the cam 472 is positioned and accessible outside the enclosure cover 402, regardless of whether the enclosure cover 402 is mechanically coupled to the enclosure body 404.
• the fastening feature 474 coupled to the end of the shaft
• the fastening feature 491 disposed on an inner portion of the enclosure body 404 can form a single piece with the remainder of the enclosure body 404, as from a cast, or can be a separate piece that is mechanically coupled to the enclosure body 404. In the latter case, the fastening feature 491 cars be mechanically coupled to the enclosure body 404 using one or more of a number of coupling methods, including but not limited to fastening devices, welding, mating threads, and compression fittings.
• the fastening feature 491 can include one or more of a number of features that allow for a uniform and/or controlled flame path 469 around the perimeter of the body flange 442 when the enclosure cover 402 is mechanically coupled to the enclosure body 404.
• the back side 439 ⁇ : . ⁇ .. the side furthest away from the mating surface of the body flange 432 when the body flange 432 is mated against the cover flange 422 to create the flame path 469) of the fastening feature 491 can form an obtuse angle 441 with the top end 443 of the enclosure body 404.
• the fastening feature 474 rotates with the cam 472 into the closed position, the fastening feature 474 is forced further away from the mating surface of the body flange 432 when the body flange 432 is mated against the cover flange 422 to create the flame path 469.
• the flame path 469 can be controlled, at least in part, by the degree of the obtuse angle 441, the length of the shaft 473, and/or the contour of the fastening feature 474.
• the fastening feature 474 can have an oblong (e.g., rectangular, oval) shape with a long side and a short side, so that the long side of the fastening feature 474 contacts the back side 439 of the fastening feature 491 when the cam 472 is in the closed position.
• the fastening feature 474 rotates (e.g., 90°) so that the short side of the fastening feature 474 is proximate to the back side 439 of the fastening feature 491.
• An example of another feature of the fastening feature 491 that can allow for a uniform and/or controlled flame path 469 around the perimeter of the body flange 442 when the enclosure cover 402 is mechanically coupled to the enclosure body 404 is one or more contours along the back side 439 of the fastening feature 491.
• contours can include, but are not limited to, a slot (e.g. , to hold the fastening feature 474 in the closed position), a curvature, a ridge, and a textured surface.
• the fastening feature 474 can form a single piece with the shaft 473 of the cam 472.
• the fastening feature 474 can be a separate piece that is mechanically coupled to the shaft 473 using one or more of a number of coupling methods, including but not limited to fastening devices, welding, mating threads, and compression fittings.
• the fastening feature 474 can be fixed or moveable relative to the shaft 473, If the fastening feature 474 is moveable relative to the shaft 473, then the fastening feature 474 can be adjusted to provide for a. flame path 469 having desired (or required) characteristics,
• the fastening feature 474 can have one or more of a number of features to allow for a more uniform and/or controlled flame path 469 around the perimeter of the body flange 442 when the enclosure cover 402 is mechanically coupled to the enclosure body 404, Examples of such features can include, but are not limited to, a spiral shape, a curved mating surface, and a textured mating surface. Such features of the fastening feature 474 can complement a corresponding feature of the fastening feature 473,
• the engagement features 425 and/or the engagement features 435 can move when the fastening device 410 moves between the open position and the closed position.
• the cam 472 may only be able to rotate approximately 90° between the open position and the closed position.
• Example embodiments of fastening devices for explosion-proof enclosures resist explosion and/or hydrostatic forces by maintaining a flame path where the cover flange and the body flange are coupled. Further, using the example fastening devices described herein and other embodiments of these example fastening devices allows for efficient and effective coupling and/or decoupling of the cover and the body of the explosion-proof enclosure. In addition, using example embodiments of fastening devices allows for increased flexibility with regard to where components are positioned on the cover and/or where conduit can be manually coupled to the explosion-proof enclosure. Further, using example embodiments of fastening devices for explosion-proof enclosures allows the flame path to exist within the requirements of one or more standards and/or regulations for explosion-proof enclosures. Example embodiments leverage the weight of the enclosure cover to interlock the various mating features (e.g., securing features, engagement features) of the enclosure cover and the enclosure body.
• mating features e.g., securing features, engagement features
• fastening devices for explosion-proof enclosures are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of this application.
• a fastening device does not need to include a bracket and/or a cam.

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• Casings For Electric Apparatus (AREA)
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• 2013
  • 2013-09-13 US US14/025,992 patent/US9272821B2/en active Active
• 2014
  • 2014-09-11 CA CA2923850A patent/CA2923850C/en active Active
  • 2014-09-11 WO PCT/US2014/055234 patent/WO2015038803A1/en active Application Filing
  • 2014-09-11 CN CN201480061867.6A patent/CN105745159B/zh active Active
  • 2014-09-11 DE DE112014004200.5T patent/DE112014004200T5/de active Pending

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